Find the next number in the sequence

5 12 24 36 ?

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

There is a shop where written:
Buy 1 for $1
10 for $2
100 for $3
I needed 999 and still only paid $3. How could this be financially viable for the shop-keeper?

I noticed one of the words in the oxford dictionary is spelled incorrectly. What about you?

It has five wheels, though often think four, You cannot use it without that one more, You can put things in it, you can strap things on top, You can't find it in the market, but you can still go shop. What is it?

John was drowned by he was not wet. How?

I look at you, you look at me, I raise my right, you raise your left. What am I?

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

Why did the Girl throw the butter out of the window?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?